Targeting AML Mitochondria by Ceramide

摘要 这项提议的长期目标是开发一种基于机制的治疗药物，用于治疗 人类急性髓系白血病(AML)，这是美国最致命的癌症之一。尽管 在治疗方面的一些进展，AML的存活率几十年来没有显著改善，只有极少数例外 用于特定的子类。而使用Flt3、IDH和Bcl2抑制剂的靶向治疗增加了反应 值得注意的是，存活时间只延长了几个月。因此，新的和创新的治疗方法 需要药物来改善AML患者的生存结果。神经鞘脂神经酰胺，一种新兴的 肿瘤抑制因子脂质，介导对各种应激刺激反应的抗增殖信号事件， 包括酪氨酸激酶抑制剂(TKIs)。我们已公布和未公布的数据表明， C18-神经酰胺的表达可能在AML的病理生理、进展和耐药中起重要作用。这些数据 还揭示了分子和药理学工具对C18-神经酰胺的重组导致 抑制AML生长，并有助于克服耐药性。因为在药理学上的挑战 在传统的外源性短链神经酰胺的基础上，我们开发了新型的线粒体靶向吡啶- C18-神经酰胺(PYR-Cer)类似物，可诱导癌细胞有丝分裂和抑制肿瘤。这些皮尔瓷器 类似物表现出更高的水溶性、细胞膜通透性和癌细胞选择性线粒体 摄取，与不带电的常规神经酰胺相比。PYR-CER类似物，如LCL461(专利 第I类)或LCL768(第II类)在离域的pi-电子系统中包含正电荷。这就导致了 药物优先定位于癌细胞/组织中带高负电荷的线粒体 华宝效应。PYR-Cer在线粒体中的积聚通过诱导细胞死亡而导致癌细胞死亡 通过减少细胞能量的产生和减少其他重要大分子的合成来促进有丝分裂， 比如核苷酸。PYR-Cer对有丝分裂的诱导作用在癌细胞 暴露在普通ROS/RNS诱导剂亚硒酸钠下，导致Drp1激活和线粒体分裂。 因此，我们合成了一种新的(II类)亚硒酸钠偶联的吡咯类似物药物，命名为 Sose-C18-PYR-Cer(LCL768)选择性诱导AML在位和在位有丝分裂依赖性细胞死亡 活着。基于这些数据，我们的目标是开发LCL768作为治疗AML的抗癌药物。在……里面 这些可行性研究，我们将：1)验证PYR-Cer药物靶向AML线粒体的机制 2)测定LCL768的生物活性、毒性、药代动力学和抗AML活性 在活体内。我们将确定可能的偏离目标的影响、最大耐受剂量(MTD)、 LCL768在不同模型中的药代动力学/药效学特征及抗AML作用。这些措施包括 药物敏感与耐药的AML异种移植、AML PDX和原发AML原始细胞。这一阶段的可行性 研究将有助于LCL768第二阶段应用的商业开发。

SUMMARY This proposal's long-term objective is to develop a mechanism-based therapeutic drug for the treatment of human acute myeloid leukemias (AML), which are among the deadliest cancers in the United States. Despite some advances in treatment, survival for AML has not improved significantly in decades, with rare exceptions for specific subclasses. While targeted therapies with FLT3, IDH, and Bcl-2 inhibitors have increased response rates significantly, survival has been extended only by several months. Thus, novel and innovative therapeutic drugs are needed to improve the survival outcomes of AML patients. The sphingolipid ceramide, an emerging tumor suppressor lipid, mediates anti-proliferative signaling events in response to various stress stimuli, including tyrosine kinase inhibitors (TKIs). Our published and unpublished data suggest that decreased levels of C18-ceramide might be critical in the pathophysiology, progression and drug-resistance of AML. These data also revealed that reconstitution of C18-ceramide by molecular and pharmacologic tools results in the suppression of AML growth, and help overcome drug resistance. Because of pharmacologic challenges of the conventional exogenous short-chain ceramides, we have developed novel mitochondrial targeted pyridinium- C18-ceramide (Pyr-Cer) analogs that induce cancer cell mitophagy and tumor suppression. These Pyr-Cer analogs exhibit increased water solubility, cell-membrane permeability, and cancer cell-selective mitochondrial uptake, compared to uncharged conventional ceramides. Pyr-Cer analog drugs, such as LCL461 (patented Class I) or LCL768 (Class II), contain a positive charge at a delocalized pi-electron system. This then results in preferential localization of the drug into highly negatively charged mitochondria in cancer cells/tissues due to the Warburg effect. The accumulation of Pyr-Cer in mitochondria results in cancer cell death via induction of mitophagy by reducing cellular energy generation and decreasing the synthesis of other vital macromolecules, such as nucleotides. This effect of Pyr-Cer on mitophagy induction is further increased when cancer cells are exposed to general ROS/RNS inducer sodium selenite that causes Drp1 activation and mitochondrial fission. Thus, we have generated a new (Class II) Pyr-Cer analog drugs conjugated with sodium selenite, named as SoSe-C18-Pyr-Cer (LCL768), which selectively induced mitophagy-dependent cell death in AML in situ and in vivo. Based on these data, our goal is to develop LCL768 as an anti-cancer drug for the treatment of AML. In these feasibility studies, we will: 1) Validate the mechanism by which Pyr-Cer drugs target AML mitochondria by mitophagy in vitro; and 2) Determine bioactivity, toxicity, pharmacokinetics and anti-AML activity of LCL768 in vivo. We will determine the possible off-target effects, maximum tolerated dose (MTD), pharmacokinetic/pharmacodynamic profiles and anti-AML effects of LCL768 in various models. These include drug sensitive versus resistant AML xenografts, AML PDXs, and primary AML blasts. This Phase I feasibility study will help the commercial development of LCL768 for a Phase II application.